Mobile communication technology has greatly advanced in recent years, as evident by the high performance digital mobile phones currently available. Mobile communication has been made available with almost 100% coverage area in many regions of the world following the demand of the users. Users wish to be able to communicate via their mobile phone (mobile stations) from anywhere they are.
As a consequence, the number of mobile stations and the number of communications links established is increasing. In addition, the amount of data transferred over a communication link is steadily increasing as it is not only desired to transfer voice messages or short messages with high quality but also increasing amounts of data, i.e. for images, movies or music etc.
In order to be reachable, a base transceiver station (BTS) has to be within the range of the mobile station. A communications link is then established between the mobile station and the BTS in which communications data are sent and received from the mobile stations and the BTS by an RF signal. The BTS transfers the communications data further into telephony or other communication networks.
Mobile service providers have to ensure that their clients can have access to a BTS almost everywhere they are. Therefore BTSs have to be distributed in order to achieve a high coverage area. In addition, a sufficient number of BTS has to be installed in urban areas in which large numbers of mobile communication have to be performed concurrently.
Modern BTS have to cover a wide frequency bandwidth and a high dynamic range.
In order to provide good access, antennas of BTS are usually placed in exposed places such as roof tops, tower tops or on masts, so that they are not shielded by walls or the landscape itself and the area covered can be maximized.